Projects enable the grouping of quotations, jobs/sales orders, invoices, etc., together to make them easier to track. Usually a project will be specific to one customer but this doesn't have to be the case.
Use a project to:
Track costs against budget
Track invoices against expected invoices
Merge job/sales order into one invoice or delivery note
Manage tasks across a project
Store documents
Learn more: project tracking in Zigaflow